1. Field of Invention
The present invention relates to an apparatus for and method of controlling liquid-crystal-display (LCD) shutter glasses and, more particularly, to an apparatus and a method capable of alternately making the right and left LCD-type shutter of the LCD shutter glasses transparent. An observer who wears the said LCD shutter glasses controlled by the said apparatus to stare any planar picture will feel the three-dimension effect of said picture.
2. Description of Prior Art
With the arrival of the multimedia era and the advancement of technology, three dimensional image displaying systems has become an integral function of video game software, especially when building a three dimensional application software on a PC with the accompaniment of LCD Shutter Glass or Head Mounted Display. With the above setup, consumers can experience virtual reality. Using LCD Shutter Glass as an example, binocular disparity is commonly used to create depth perception and three-dimensionality such that an observer who wears the said LCD shutter glasses to watch any planar picture will feel the three-dimension effect of said picture.
Binocular disparity refers to the condition where when one stares at an object, there is a slight inconsistency between the images projected onto the left and right retinas due to different sight angles for the left eye and the right eye. After the optic nerves process. the slightly inconsistent images the viewer experiences the sensation of three-dimensional effect. In simpler terms, if a special method is used to form a first and second image from a purely two dimensional picture, and there exists between the first and second images a fixed discrepancy, and the left and right eyes are each limited to view only either the first or second image, then a three-dimensional effect can be achieved through binocular disparity. The function of the LCD Shutter Glass is as follows: when an image meant for left-eye-viewing is displayed, the LCD Shutter Glass""s left lens transmits light while the right lens blocks light, and vice versa. Via the alternating light blocking and light transmitting functions of the lenses, the viewer experiences effect of three-dimensionality.
Investigation shows that traditional 3D imaging systems (such as D3D, OpenGL,) mostly utilize the following principle (please refer to FIG. 1):
Hypothesize that an object 11 is placed in a virtual space, and the object""s outline can be sketched by connecting a first apex 111, a second apex 112, a third apex 113, a fourth apex 114, and so on. In simpler terms, any object can be sketched by tracing the vectors of certain apexes. Therefore, if one wishes to display the object 11 on the screen 13, a first viewpoint 12 (for example the left eye of a person) could be of assistance, projecting the first apex 111 onto the computer screen 13, making it a first displaying point 141. The procedure is repeated for the second apex 112, the third apex 113, and the fourth apex 114, making them show up on the screen 13 as a second displaying point 142, a third displaying point 143, and a fourth displaying point 144, respectively. Then using a 3D Rendering Engine habitually employed by the industry, connect and outline the first displaying point 141, the second displaying point 142, the third displaying point 143, and the fourth displaying point 144. Subsequently, a first 3D image 14 is displayed on the computer screen. Only this kind of 3D image cannot create depth perception as binocular disparity can, and therefore is unable to supply the sensation of three-dimension one experiences in the real world. Hence, the invention refers to images made by a single viewpoint using linear perspective xe2x80x9c3D images,xe2x80x9d not real xe2x80x9cthree-dimensional images.xe2x80x9d
The solution is to pair the first apex 111 with a second viewpoint 15 (such as a person""s right eye), and project a fifth displaying point 161. Then, repeat the procedure with the second apex 112, the third apex 113, and the fourth apex 114 to project onto the screen 13 a sixth displaying point 162, a seventh displaying point 163, and a eighth displaying point 164. After processing by a 3D Rendering Engine a second 3D image 16 is displayed on the computer screen. There exists a certain discrepancy between the first 3D image 14 and the second 3D image 16, and the viewer""s left eye is made to view only the first 3D image 14 while the right eye views only the second 3D image 16. As a result, the viewer experiences three-dimensionality due to binocular disparity.
Yet the above-described method of producing binocular disparity is limited in efficiency. Projecting the first apex 111 onto the computer screen to create the first displaying point 141 needs to be synchronized with matrix calculation. To convert the spatial coordinates of the first apex 111 into the computer coordinates of the first displaying point 141 requires a certain amount of time. Since binocular disparity is desired, it is necessary to once again employ matrix calculation to convert the first apex 111""s spatial coordinates into the fifth displaying point 161. Clearly, the method described above requires many repetitions of the matrix calculation process before other procedures can be employed. Moreover, the matrix calculation process is very time-consuming, and naturally hinders the following imaging process. Therefore this repeated use of the matrix calculation process is mostly applied to xe2x80x9cstill three-dimensionalxe2x80x9d images; it fails to deliver ideal results when applied to xe2x80x9creal-time image three-dimensional imagesxe2x80x9d due to the extended processing time.
As the aforementioned, the 3D image obtained via processing by a traditional 3D Rendering Engine is still a two dimensional image. The 3D Rendering Engine saves the image""s content in the frame buffer, and uses the scanning circuit to access the information in the frame buffer, and employs the interlace scan method to exhibit the 3D image information on the display screenxe2x80x94please refer to FIG. 2(a). FIG. 2(a) is a block diagram showing the relationship between a traditional 3D Rendering Engine 21, a scanning circuit 22, a address-translating circuit 23, and a frame buffer 24. A computer""s Memory address is essentially an one dimension line vector, and the 3D image information in the frame buffer is composed of many pixel. For example, if the upper left comer of the screen 25 is an original point 26, the real Memory address of any pixel P with coordinates (x,y) should be (please refer to FIG. 2(b))
Pixel P""s real address=P0+y*pitch+x
Where P0 is the real Memory address of the original point 26 at the upper left corner of display screen 25; pitch is the width of every scanning line in the frame buffer 24 (please refer to FIG. 2(a)). The 3D Rendering Engine desires to sketch a 3D image (this image is still a two dimension image), so it requires the assistance of the said address-translating circuit 23 to convert every pixel in the 3D image""s frame buffer before it""s able to save information in the real Memory address. Similarly, when the scanning circuit 22 desires to display on the screen 25 every pixel information in the frame buffer based on an interlacing manner, the scanning circuit 22 also needs the address-translating circuit 23 to obtain the pixel""s real address, then send the information saved in the real address to the screen 25. Traditionally, the display design of a regular stereoscopic system is divided into non-interlace and Interlace display scan. A three-dimensional visual display application of non-interlace display scan is more complicated in design because the left and right eyes must each be equipped with a display screen and shod. In concern with the mutual accommodation of the non-interlace processing systems and the ready-made three-dimensional images, it is seldom applied because the ready-made three-dimensional images usually designed for interlace processing system. Therefore, most stereoscopic displays utilize Interlace scan, placing two images with image discrepancy (the first 3D image 31 and the second 3D image 32) in separate memory addresses. Please refer to FIG. 3, which shows the memory placement relationship between two 3D images created in the traditional method by a 3D Rendering Engine. Yet the placement method of the two separate frame buffers in the memory inevitably causes problems for traditional scanning circuit 22. In order to display on the screen the aforementioned first 3D image 31 and second 3D image 32 in an interlacing manner, another kind of address-translating circuit, not the traditional address-translating circuit 23, is needed.
The invention targets the above problems, providing a three-dimensional image processing apparatus and method, effectively and efficiently render 3D images and then produce really three-dimensional effect. The invention""s method of processing three-dimensional images avoids repetition of matrix calculation, and is effective in setting the picture frame""s memory address. Hence, it is suitable for three-dimensional images with real-time image. Moreover, the three-dimensional image processing apparatus proposed by the invention doesn""t need to alter the address-translating circuit 23; it only needs an additional and simple electric circuit. As a result, there will be a lowering of manufacturing costs. To further illustrate the invention""s method, structure, and characteristics, we herein elucidate the more successful incidences of the invention with the accompaniment of diagrams. However, the following elucidation is of a xe2x80x9cbetter case scenario,xe2x80x9d and of course cannot be used to limit the range of the invention""s actual application. Therefore, any equal or similar variation on the spirit of the invention set forth in the patent application should fall within the scope of the invention""s patent application.